When a patient is undergoing a medical procedure that requires the infusion of a liquid into their circulatory system, be it venous or arterial, the introduction of a significantly-sized gas bubble (also known as a “gas volume”, or a “gas bolus”, etc.) into the patient's vascular system must be avoided, since the creation of a gas embolism can result in serious morbidity and even death.
There are two general categories of gas embolisms: venous and arterial. The primary difference between the two depends on the path by which the gas enters the vascular structure.
There are two general causes for the introduction of gas into either the arterial or venous systems:                (i) from instrumentation, such as accidental air injection through tubing, catheters, injectors, fluid warmers, etc.; and        (ii) from physical conditions relating to the patient, such as sub-atmospheric pressure in incised non-collapsed veins or veins in a coagulated operative field, etc.        
Available data indicates that 2+ cc's of air per kilogram of body weight, if injected into the venous system, is lethal. Smaller amounts can cause various degrees of morbidity. To put this in perspective, the air in an empty 4 ounce cup, if injected into the veins of a 170 pound person and not treated immediately, would typically prove lethal.
Thus, there is a need for a system for detecting and removing a gas bubble from a liquid infusion line prior to the gas bubble entering the vascular system of the patient.